Sprint is introducing a new wireless plan that guarantees new and existing customers unlimited voice, text and data plans.

The plan called 'Sprint Unlimited Guarantee' is applicable to anyone who sign up for Sprint's new 'Unlimited,' 'My Way plan' or 'My All-in plan', which are available starting July 12.

"The Sprint Unlimited Guarantee allows our customers to lock-in unlimited talk, text and data not for just the next two years, but for life. Sprint customers won't have to worry about their wireless bill or managing their family's wireless usage. While other wireless providers are moving away from unlimited service, Sprint champions it," Sprint CEO Dan Hesse said.

The new Unlimited, My Way and My All-in rate plans feature unlimited talk, text and data while on the Sprint network for $80 per month. With the Unlimited, My Way plan, Sprint customers can also customize their wireless plan including mixing smartphones and basic phones, selecting their data options, and adding up to 10 lines all on the same account. As customers add additional lines to their account, the more they can save on each line every month. For example, on lines four to 10, Sprint's customers can get unlimited talk, text and data for as little as $50 per month.

How the Unlimited, My Way Plan Works:

- Customers first select the number of lines; all lines come with unlimited talk to any wireline or mobile phone and text.
- Customers then choose their data for each line: $30/month for unlimited data on smartphones or $10/month for unlimited data on basic phones. Additional options include $20 for 1GB of data on smartphones or basic phone users can choose not to add data to their account.
- Customers also have the choice to activate mobile hotspot functionality on their smartphone for $10 per month for 1GB of data on the Sprint network.

In addition, Sprint is offering smartphone customers the 'My All-in' plan with unlimited talk, text and data while on the Sprint network and 5GB mobile hotspot usage for $110.

How The Sprint Unlimited Guarantee Works:

- All customers on an Unlimited, My Way plan or a My All-in plan will have unlimited talk and text guaranteed for the life of the line of service.
- Customers who select unlimited data on an Unlimited, My Way plan or a My All-in plan will have unlimited data guaranteed for the life of the line of service.
- The guarantee will apply to customers as long as they remain on the plan, meet the terms and conditions of the plan and pay their bill in full and on-time.
- The guarantee is non-transferrable.

Both AT&T and Verizon Wireless have ditched unlimited data offerings to new customers. They have both introduced shared-data plans that allow all of a family's devices to share a pool of monthly data usage.

Sprint, the third-largest U.S. wireless carrier, is now under the control of Japanese investment firm SoftBank.